使用clang和gnustep的Objective-C中的简单Hello World无法编译

Question

系统:

64bit Ubuntu Lucid
GNUStep
clang/LLVM

test.m

#import <Foundation/Foundation.h>

int main(int argc, char * argv[]){
    NSLog(@"Hello world!\n");
    return 0;
}

编译命令行:

clang -fobjc-gc -I /usr/lib/gcc/x86_64-linux-gnu/4.4.3/include -I /usr/include/GNUstep/ -I /usr/lib/gcc/x86_64-linux-gnu/4.4.3/include-fixed/ -L /usr/lib/GNUstep/ -L /usr/lib64/ -fconstant-string-class=NSConstantString -rpath /usr/lib64 -Xlinker -lgnustep-base  test.m -o Test

错误:

/usr/bin/ld: /usr/lib64//libgnustep-base.so: undefined reference to symbol '__objc_exec_class'
/usr/bin/ld: note: '__objc_exec_class' is defined in DSO /usr/lib64/libobjc.so.2 so try adding it to the linker command line
/usr/lib64/libobjc.so.2: could not read symbols: Invalid operation
clang: error: linker command failed with exit code 1 (use -v to see invocation)

使用GCC时,它编译得很好,但是clang没有.

Answer 1

在全新安装的Ubuntu 12.10上,我安装了以下软件包:

$ sudo apt-get install build-essential
$ sudo apt-get install clang
$ sudo apt-get install gnustep
$ sudo apt-get install gnustep-make
$ sudo apt-get install gnustep-devel
$ sudo ln -s /usr/lib/gcc/i686-linux-gnu/4.7/include/objc /usr/local/include/objc

(最后的符号链接是正确定位objc.h头所必需的)

然后我编译了test.m文件,如下所示:

$ clang -o test test.m -I `gnustep-config --variable=GNUSTEP_SYSTEM_HEADERS` \
                       -L `gnustep-config --variable=GNUSTEP_SYSTEM_LIBRARIES` \
                       -lgnustep-base -fconstant-string-class=NSConstantString \
                       -D_NATIVE_OBJC_EXCEPTIONS \
                       -lobjc

tux@ubuntu:~/Desktop$ ./test 
2012-11-20 11:02:08.184 test[11856] Hello world!

*编辑

在新的10.04-64位上,这允许编译就好了:

$ sudo apt-get install build-essential
$ sudo apt-get install clang
$ sudo apt-get install gnustep-devel
$ sudo ln -s /usr/lib/gcc/x86_64-linux-gnu/4.4.3/include/objc/ /usr/local/include/objc